The relative importance of routes and sources of wound contamination during general surgery. I. Non-airborne

A study was undertaken to determine the relative importance of some sources, routes of transmission, and measures to prevent bacteria entering the wound during biliary tract surgery. When bacteria were growing in the bile they accounted for the majority (greater than 99%) of the bacteria found in the wound. However, when the bile was sterile the skin bacteria at the incision site were found to make a substantial contribution to the wound flora. The difference in the total wound contamination between a patient who had practically no skin bacteria and one who had an average amount was in the region of 17-fold. No transfer of skin bacteria from the surgical team through perforated gloves or by direct contact from the surface of operating gowns was demonstrated. Ten of the patients studied had septic wounds. Five of these were infected by bacteria from the bile.

Dose-dependent inner ear changes after i.v. administration of cisplatin

The effect on the cochlear and vestibular surface structures in the inner ear of guinea pigs receiving different doses of cisplatin was studied in three groups of animals. A semi-quantitative analysis showed that cisplatin induced outer hair cell (OHC) damage which developed over days, was dose-dependent and that repeated intraperitoneal injections of a low dose of cisplatin caused OHC changes comparable to a single intravenous injection. The range of OHC damage varied generally between the three rows of OHCs, but in the most severely damaged cochleas the changes were equally distributed between the rows in the basal turn. The inner hair cells (IHCs) and sensory cells of the vestibular end organ were unaffected up to five days after an intravenous injection of cisplatin.

Degeneration of the organ of Corti following intravenous administration of cisplatin

The development of acute morphological changes in the cochlea was studied in guinea pigs given one intravenous high-dose injection of cisplatin. In the light microscope three major stages of degeneration in the organ of Corti could be recognized: 1) an initial swelling of the Hensen's cells and protrusion of the Deiters' cells into the space of Nuel enclosing the outer hair cells, 2) a gradual degeneration of the outer hair cells together with a vacuolization in the region of the base of the inner hair cells, 3) a collapse of the Reissner's membrane and the entire organ of Corti with different degrees of damage to the inner hair cells. Sporadic bulging of the marginal cells of the stria vascularis into the endolymphatic space could be observed 4 days after injection.

Cisplatin: effects on the stretch receptor neuron of the crayfish

The effects of cisplatin on electrical and mechanotransducer properties of the crayfish stretch receptor neuron was studied using a microelectrode voltage clamp technique. In the stretch receptor neuron, negligible changes in membrane capacitance, leak conductance, resting membrane potential, potential-dependent currents or mechanoreceptor current were seen either on acute cisplatin treatment or after long-lasting treatment for up to 2 weeks. The inhibitory GABA-sensitive synapse on the neuron was not affected by cisplatin. The cisplatin cytotoxicity on sensory neurons such as outer hair cells of the organ of Corti cannot be explained by direct effects on ionic channels of these cells including stretch-activated channels.

High-dose cisplatin treatment: hearing loss and plasma concentrations

Fifty-four patients with metastatic cancer were followed audiometrically during high-dose (100-120 mg/m2) cisplatin chemotherapy. Eighty-one percent of the patients showed significant changes in air-conduction hearing thresholds after completion of therapy. Thirteen percent sustained a significant hearing handicap. An interindividual variation was found, ranging from severe hearing loss after the first course to unaffected hearing after three courses. The ototoxic effect was not increased by pre-existing hearing loss, but was slightly increased by age. The risk was determined more by the amount of the single dose than by the cumulative dose. The further ototoxic effect could not be predicted on the basis of the audiogram after the first course. Peak plasma concentration of platinum was measured in eight patients, and no ototoxic changes were noted below a concentration of 1 microgram/L.

An investigation of occlusive polyester surgical clothing

The bacterial dispersion rate of people wearing operating room clothing made from several types of polyester fabric was compared to conventional cotton clothing, total-body exhaust gowns and disposable clothing. Airborne bacteria were measured in a chamber, three ultra-clean air operating rooms and a conventionally ventilated operating room. The polyester clothing was demonstrated to be much superior to conventional cotton clothing and at least as good as the total-body exhaust gowns and disposable clothing.

Biliary tract surgery: a bacteriologic and epidemiologic study

The sources and routes of postoperative wound infections were prospectively studied in 440 patients undergoing biliary tract surgery. The overall infection rate was 7.3%. Specimens for culture were taken peroperatively from bile, liver bed and subcutaneous fat in 402 patients and also from skin in 64. Of the 126 patients with positive bile culture (31%), all but one had bacteria in the other intraoperative cultures, with high counts of bile bacteria in liver bed and transfer of such bacteria to subcutaneous fat in 81.2%. The wound infection rate in this group was 12.8%. Of the 276 patients with sterile bile, more than 90% had bacteria in the other intraoperative cultures. The degree of contamination was low, with dominance of typical skin bacteria, and the group wound infection rate was 3.2%. In 19 postoperative wound infections intraoperative cultures were available for comparison. Eleven of these infections were classified as endogenous, six as exogenous and two as of uncertain origin. S. aureus was uncommon in bile and intraoperative wound cultures, but was almost as common as E. coli in the etiology of postoperative wound infections, indicating high pathogenicity.

Changes of stapedius reflex and hearing threshold in patients receiving high-dose cisplatin treatment

The value of stapedius reflex (SR) measurement in the clinical management of the ototoxic side-effect of cisplatin was examined in 24 patients who had received a dose of 100-120 mg/m2. The main finding was a frequent but inconsistent deterioration of the SR threshold (SRT) at 3 and/or 4 kHz, usually with a moderate rise of the hearing threshold (HT) in the frequency range 3-8 kHz. A hearing loss exceeding 60 dB HL is detected with high probability as an SRT deterioration. None of the patients showed any influence on the SRT before the HT rise could be detected. The SR test cannot replace pure-tone audiometry for the identification of cisplatin ototoxicity. The pathological SR results observed in this study indicated a cochlear lesion. It was not possible to identify those patients most susceptible to ototoxic changes from the pretreatment results of the SR test.

Vibratory stimulation as a treatment alternative in patients with tinnitus

We evaluated the effect of vibratory stimulation on 10 patients with tinnitus and controlled it in a double-blind crossover trial against the sound stimulus delivered by the same apparatus. Five patients reported decreased intensity of tinnitus during treatment when vibratory stimulation was used, as opposed to 1 patient who reported decreased intensity of tinnitus when only the sound stimulus was used. There were no significant differences between the groups in the reduction of the unpleasantness associated with tinnitus. No longterm effects of treatment were seen.

The ototoxic effect of cisplatin on guinea pigs in relation to dosage

The effect on the electrophysiological hearing thresholds and the endocochlear DC potential (EP) was studied in four groups of guinea pigs receiving different doses of cisplatin. By multiple low-dose intraperitoneal injections a permanent hearing loss was produced without a permanent decrease of the EP. On the other hand, when cisplatin was given as a single high-dose intravenous injection, there was an impairment of the electrophysiological hearing thresholds and EP, depending upon the level of cisplatin dose. It is concluded that cisplatin-induced hearing loss is not necessarily a sequela to a loss of EP.

The combined effect of cisplatin and furosemide on hearing function in guinea pigs

The effect of the combined administration of cisplatin and furosemide on the electrophysiological hearing thresholds and endocochlear DC potential (EP) was studied in guinea pigs. A lack of interaction was found in animals given repeated intraperitoneal injections of a low dose of cisplatin with a pharmacological dose of furosemide. An ototoxic interaction occurred when a moderately high dose of cisplatin was administered intravenously at a time when the strial function was most affected by a very high dose of furosemide. The interaction was seen both as a decreased EP and a pronounced shift of auditory thresholds. It is concluded that the stria vascularis plays a role in the ototoxic mechanism of cisplatin.

Acupuncture for the alleviation of tinnitus

The present study describes the effect of acupuncture in 12 patients with tinnitus. The patients were referred from the Department of Audiology, Karolinska Hospital, where their hearing and tinnitus were assessed. None of the patients had benefited from previous treatment for tinnitus. The selection of acupuncture points depended on the individual and was, to a limited extent, based on traditional Chinese medicine (TCM). Local points such as Si 19, Sj 17, and Sj 21 were fairly standard; distal points took into account associated problems of the patient, but were also points recommended in TCM for tinnitus. Ten treatments were attempted within a 6- to 12-week period. The treatments were carried out weekly or biweekly depending on the availability of patient and acupuncturist. Six patients had transient effects and noise reduction. However, no positive long-term results were obtained. Similarities between the experience of tinnitus and of pain are discussed in light of these findings.

Ototoxicity of cisplatin in gynaecological cancer patients

The ototoxic side effect of a moderate dose of cisplatin was studied by regular audiometric investigations in 186 women with gynaecologic cancer. Cisplatin was given in a dose of 50 mg/m2 body surface by intravenous infusion every 4 weeks. High-frequency hearing loss occurred in 40 patients (22%), but in no single case was a significant change observed in the frequency range of 0.5-2 kHz. Older patients showed a statistically significant greater incidence of audiometric changes, but the pretreatment audiogram was not a predictor for ototoxic changes. It is concluded that a moderate dose of cisplatin does not effect the ability to communicate.

Ototoxicity of cisplatin

Ototoxicity is one of the unwanted side effects of cisplatin treatment. The first sign of hearing loss usually appears 3-4 days after the drug administration and occurs primarily in the higher frequencies. One hundred and eighty-six women treated with a moderate dose of cisplatin (50 mg/m2 every 4 weeks) for gynaecological cancer were studied. No significant loss of hearing was detected in the speech frequency range. Since the cisplatin concentration in the inner ear is highest after a single high dose injection, systemic audiometric monitoring is advisable during cisplatin therapy with single high dose regimen.

Selected pathological findings in the human cochlea

Out of a material of 45 patients with known audiograms where the inner ears had been fixed with an aldehyde within 7 h after death, 4 cases were chosen for detailed morphological examination. The general findings in the ageing human cochlea are presented as well as the findings in the 4 specific cases.

Cis-platin ototoxicity in previously noise-exposed guinea pigs

The ototoxic effect of Cis-platin on guinea pigs was assessed with frequency-specific brainstem audiometry in the frequency range 0.8-20 kHz. The animals had a noise-induced hearing loss in one ear before Cis-platin treatment. The loss of threshold showed a large inter-individual variability, with a rapid increase above a hypothetic threshold dose. In the noise-exposed ear the total loss was larger, but the additional ototoxic effect was smaller than on the non-exposed side. The hearing loss was independent of pigmentation. in conclusion, there is no potentiation between noise-induced hearing loss and Cis-platin. The data support regular audiometric control before and during Cis-platin treatment for easy detection of incipient hearing loss, before the speech frequency range is affected.

Fecal bacterial flora of four nordic population groups with diverse incidence of large bowel cancer

Fecal samples were collected and biologically examined from 4 population groups, exhibiting a 3-fold range in colon cancer incidence, in Denmark and Finland. Carrier rates and counts per gram feces of several aerobic as well as anaerobic genera, including nuclear dehydrogenase-producing clostridia, were calculated. The results obtained with the described method did not confirm a relationship between colon cancer incidence and carrier rates of intestinal bacteria.

Wound infections after surgery in a modern operating suite: clinical, bacteriological and epidemiological findings

A prospective study of 2983 operations in general and orthopaedic surgery during 3 years performed in four operating theatres in a modern operating suite was carried out in order to evaluate the importance of airborne infection. Weekly nose-and-throat samples were taken from the surgical staff and pre-operative samples were taken from the nose, throat, skin and perineum of the patients. The air contamination was followed by using settle plates, which showed low mean counts of total bacteria of between 9 and 15 c.f.u./m(2)/min, with mean counts of Staph. aureus of between 0.03 and 0.06 c.f.u./m(2)/min. No correlation was found between the total number of bacteria and the incidence of post-operative infections or between the amount of Staph. aureus in the air and post-operative Staph. aureus infections. It was concluded that further increases in ventilation could, at best, only marginally affect the incidence of post-operative infection.The post-operative wound-infection rate was 9.0%. In various types of surgery, the infection rates varied from 5.3% in clean operations to 47.6% in dirty surgery. About one third of the infections were classified as moderate or severe.Adverse patient factors, such as immunodeficiency, steroid treatment, intensive care, etc., increased the rate to 15.0%; in ;normal' patients it was 3.8%.Among the bacteria isolated, gram-negative bacilli (31% of wounds), often together with other bacteria, and Staph. aureus (28%) predominated, but in 25% no specimens were taken.Of 76 post-operative Staph. aureus infections, 32 were caused by the patients' own strains, and of the remaining 44 infections, 22, or 8% of all infections, could be traced to strains present in the air and/or the respiratory tracts of staff during the operation.The length of pre-operative hospital stay had no influence on the carrier rate of Staph. aureus in patients. The incidence of post-operative wound infection was significantly higher in patients carrying Staph. aureus and was even higher if these bacteria were found on the skin.Patients with wound infections stayed, on an average, 15 days longer than patients without infections. In serious infections the increase in duration of stay was > 20 days. Although infections were commoner in older patients, the average additional hospital stay of infected patients did not increase with age. If the post-operative infections studied in a concurrent retrospective study are taken into account more than 12 000 bed-days were due to post-surgical wound infections in the period studied or, in other words, some 12 beds (corresponding to 5.5% of the total) were always occupied by infected patients.

Bacterial contamination in a modern operating suite. 3. Importance of floor contamination as a source of airborne bacteria

The redispersal factor for bacteria-carrying particles from a contaminated floor was determined after mopping, blowing and walking activity. Walking gave the highest redispersal factor, 3.5 X 10(-3) m-1, which was three times higher than for blowing and 17 times higher than for mopping. The mean die-away rate for the bacteria-carrying particles used was 1.9/h without ventilation and 14.3/h with ventilation. It was calculated that in the operating rooms less than 15% of the bacteria found in the air were redispersed floor bacteria.

Bacterial contamination in a modern operating suite. 4. Bacterial contamination of clothes worn in the suite

Clean clothes in the staff dressing rooms were heavily contaminated with bacteria, mainly Bacillus sp., but Staphylococcus aureus were found on 14% and Clostridium sp. on 10% of the garments examined. A comparison of the occurrence of Staph. aureus on shirts worn by staff in wards and operating departments showed ward shirts to be contaminated more heavily and with more strains. Examination of sterile gowns worn by surgeons showed that 70% were contaminated with Staph. aureus after operation. Of the strains isolated 31% were identical with those carried by the surgeon or by the patient operated on, but for the remainder no source could be found.